Electromagnetic trip mechanism



B. E. GETCHELL.

ELECTROMAGNETIC TRIP MECHANISM.

APPLICATION FILED DEC-6| 1919.

Patented Sept. 20,1921.

UNITED STATES PATENT OFFICE.

BENJAMIN E. GETCHELL, OF PLAINVILLE, CONNECTICUT, ASSIGNOR TO THE TRTJ'M- BULL ELECTRICMANUFACTURING 00.,

RATION OF CONNECTICUT.

nnnc'rnormennric TRIP MECHANISM.

OFPLAINVILLE, CONNECTICUT, A CORPO- Specification of Letters Patent.Pate t d S t 20 1921 Application filed December 6, 1919, Serial No.343,066.

T all whom it may concern:

Be it known that I, BENJAMIN E. GETCH- ELL, a citizen of the UnitedStates of America, residing at Plainville, Connecticut, have invented -anew and useful Electromagnetic Trip Mechanism, of which the following isa specification.

My invention relates to mechanism which is particularly adapted for alow voltagewho voltage release for an inclosed electric switch.

In. such constructions it has been custo: mary to provide mechanism forholding the switch in the closed circuit position and for releasing itautomatically in case the circuit is broken or in case the voltagedecreases. Such devices customarily employ springs and naturally themoving parts require more or less force to start their move.

2 mentj Sometimes, if the voltage decreases slowly the release apparatusfails to work, particularly as regards the operation of the armature ofa solenoid such as shown in this application.

The main object of my invention is to make the release action moreositive and certain even under such conditions and insure a positivedrop of the armature rather than a gradual settling down of same.Another object is to prevent the chattering or humming of the partswhich sometimes occurs when operating on alternating current.

In the preferred form of my invention I have illustrated it as appliedto an inclosed switch with a spring actuated operating handle and asolenoid release with intermediate. latch and trip levers. The core ofthesolenoid is formed in two parts, one of which is auxiliary orsupplemental to the main part and is longtudinally movable with relationthereto. The trip lever is actuated by the dropping of the main part ofthe core.

Figure 1, is a side .view of apparatus embodying my invention, part ofthe coil and its housing being broken away to show the core and the tripmechanism, the parts being in the position they would occupy whenoperating under normal conditions with circuit ON.

Fig. 2 is a vertical sectional view on a plane at right angles to theview of Fig. 1,

the parts being in the position momentarily interior operating arm 6 inany suitable occupied in case the voltage decreases slowly and allowsthe plunger and core to descend until the flange of the auxiliaryarmature rests upon the upper part of the coil frame. A further drop ofthe core from this position causes the automatic tripp ng of the leversand release of the swltc Fig. 3, is a perspective view showing separateparts'of the core and plunger.

I have indicated a part of the switch box by the reference 5. This boxcontains the switch mechanism which of course has a movin contact memberas usual (not shown% adaplted to be opened andclosed by an arm 6. hisarm is under tension of a spring 7 which tends to open the circuit inthe switch.

Exterior of the box is the operating handle or lever 8 which isconnected to the manner.

A pivoted latch member 9 is adapted to engage the stud or projection 10on the handle 8 to hold the handle with the switch in the closed circuitposition. A trip lever 11 co-acts with one end of the latch 9 so as tonormally oppose the action of the spring 12-which tends to disengage thelatch from the handle projection 10. A spring 13 holds the trip lever 11under tension towardthe position in which it is shown in Figs. 1 and 2,that is, with the latch 9 engaging the handle projection 10.

A releasing member 14 normally raised by the spring 15 is adapted to bepushed down by the finger piece 16 so as to release the tri lever 11from the latch 9 when it is desire to manually open the switch.

The coil 17 is provided with a core having the plunger rod 18. This coreconsists of a main body 19 and the auxiliary part 20 both of which areof magnetic material. The rod is preferably of non-magnetic material so,that it does not enter into the magnetic circuit. At the upper end ofthe rod 18 is a disk 24 which overstands the horizontal arm of the triplever 11 so that when the core of the solenoid descends it strikes thehorizontal arm of the trip lever and thus upward movement until theflange 22 of the auxiliary core is free of the coil so as to preventchattering of the flange against the coil under normal conditions; thedisk 24 is also carried upward so asto free it from contact with thetrip lever 11.

When the voltage is reduced or decreased, the two-part core descendsuntil the flange 22 of the auxiliary core rests upon the coil and inthis position, the magnetic condition of the two parts of the core tendsto hold them together until the Volta e has been so much further reducedthat t e magnetic influence is no longer strong enough to hold up themain part of the core which then drops suddenly and trips the switch.

The magnetic attraction of the two parts of the core holds them togetherfor a period during which the voltage has been considerably reduced sothat when the main part of the core does separate from the auxiliarypart, the separation is sudden and causes a positive tripping of thelever 11 which in turn releases the switch.

This interrupted dropping of the main part of the core occurs whetherthe voltage is suddenly or gradually reduced and this sudden initialdrop causes the disk 24 to strike the trip lever 11 with a comparativelypowerful blow. It will be obvious that if the core descended slowly thefriction of the parts of the latch lever and trip lever might besuflicient to sustain the entire weight of the core and plunger. g

For convenience in manufacture and assembling, the parts of the solenoidand trip and latch-mechanism are preferably mounted in an auxiliaryhousing consisting of the body part 25 which surrounds the coil and thecover part 26 which surrounds the upper end of the core and the triplever and carries the latch member and the manual releasing device 14and button 16. The body part 25 is open at the bottom to ermitventilation and access to the core. he latch 9 has a shoulder 27 adaptedto be engaged by the projection 10 when resetting the handle so as tothus reset the latch 9 and allow the spring 13 to reset the trip lever-11.

I claim 1. In an electro-magnetic trip device, a coil, a verticallymovable core consisting of a main body, a plunger rod, an auxiliary coreslidable on said rod, means for limiting the vertical descent of theauxiliary core and a trip member operated by said plunger rod when thevoltage falls below a prede- 3. In an electro-magnetic trip device, a

coil, a core to be moved in one direction by and movable within saidcoil, an auxiliary core movable within saidcoil and co-acting with saidfirst mentioned core when the latter is moved to one position by the.coil under normal voltage, a trip member, means on said first mentionedcore for actuating said trip member when the voltage in the coil fallsbelow a predetermined point, said means'and trip member being out ofcontact with each other under normal voltage conditions, means forarrestin the movement of said auxiliary core wl ereby when the voltagefalls below a predetermined point both cores will move and upon thearresting of the movement of the auxiliary core the other core will moveaway therefrom and deliver a sharp blow to said trip member.

4. In an electro-magnetic trip device, a coil, a core movable withinsaid coil, a plunger rod of smaller diameter than said core and movabletherewith, a flange on said plunger rod at the end remote from saidcore, an auxiliary core slidable on said plunger rod and adaptdd toco-act with said first mentioned core, a flange upon said auxiliary corefor stopping against a part of the device for arresting the movement ofthe auxiliary core in one direction, and a trip member having a partextending between said flanges and adapted to be operated by one of saidflanges when the voltage in the coil drops below a predetermined point.

BENJAMIN E. GETCHELL.

